Variation of leaf gland volatile oil within a population of sweet gale (Myrica gale) (Myricaceae)

Summary The leaf gland volatile oils of ten sweet gale plants from a Scottish population were extracted in early summer. The results differed notably from reports of other populations in respect of the sesquiterpenes, -elemenone and germacrone, which were major components of the volatile oil. Three dihydrochalcones were also detected in the volatile oil. Variation within the population existed, particularly with respect to the relative importance of germacrone. Five plants were resampled in late summer and exhibited a marked reduction in -elemenone, a lesser reduction in germacrone and changes in the proportions of some monoterpenes.     

Effect of Humic Acid on the Bioavailability of γ-Hexachlorocyclohexane in Marsilea Minuta (L.)

Effect of various concentrations of humic acid (0.2 to 1%) on thebioavailability of -HCH in vegetative clones of theaquatic fern Marsilea minuta was studied in a staticexperimental bioassay system on different photoperiods. Additionof humic acid showed the reduction in the bioavailability of-HCH in all the photoperiods (72 hr light to 144 hrlight) at the interval of 16 hr light (L) and 8 hr dark (D) inboth aerial and submerged portion as compared to controlindicating its protective role in toxicity.     

COMBUSTIVE APPROACH FOR MEASURING TOTAL VOLATILE PHOSPHORUS CONTENT IN LANDFILL GAS

A technique was developed to measure the total gaseous phosphorus content in biogas. The amount of air needed for a neutral to oxidising flame was mixed with the biogas. The gas mixture was burnt in a closed quartz burner and the combustion gasses were bubbled through a nitric acid solution. The phosphate content in the bubbling liquid was determined with sector field ICP-MS. The technique was validated in the lab with phosphine. Afterwards the set-up was installed on a landfill. The total gaseous phosphorus content in the landfill gas, measured with the combustive technique, ranged from 1.65 to 4.44 g P/m³. At the same time the phosphine concentration in the landfill gas was determined gas chromatographically (GC). The phosphine (PH₃) content measured with GC ranged from 7.6 to 16.7 g PH₃-P/m³. Since the phosphine-P content (GC) was consistently higher than the total gaseous phosphorus content (burner/ICP-MS), the hypothesised presence of highly toxic gaseous phosphorus compounds other than phosphine could not be demonstrated.     

Response of the Ascorbate-Peroxidase of Selenastrum capricornutum to Copper and Lead in Stormwaters

The green alga Selenastrum capricornutum expresses a uniqueascorbate peroxidase, that responds to copper and lead. Attemptswere made to test if this peroxidase could be used to monitor thelevels of copper and lead in natural waters. When S.capricornutum was exposed to a stormwater sample, the specificactivity of the peroxidase in the cell extract was commensuratewith the combined copper and lead contents in the sample. Theperoxidase responses were also correlated with the 96 hr biomasstoxicity assay of S. capricornutum. However, unlike thebiomass toxicity assay, the peroxidase activity was not affectedby the anions in the samples. The use of this peroxidase can beused as a marker for testing heavy metal toxicity in the water.     

Economic and Spatial Impacts of an Existing Reserve Network on Future Augmentation

An optimization model for land reservation was developed that explicitly selects parcels in the most compact or contiguous manner possible while meeting habitat requirements and a budget limitation. The model was used to compare the effects of an existing reserve network on future parcel spatial locations and total cost. Using habitat and land value data from Josephine County, Oregon, it was found that a system of existing reserves created by various policies and overseen by different agencies can decrease future reserve compactness and contiguity, and increase total cost. This work suggests that coordinated planning can result in more efficient conservation efforts for less cost.     

CCl4体外引发自由基反应的简易实验方法

通过对不同剂量CCl4与小鼠肝匀浆温育反应液中丙二醛(MDA)含量的测定,确立了CCl4体外引发自由基反应的简易实验方法,并对实验方法进行了考核评定.同时以Hg2 对CCl4体外引发小鼠肝匀浆自由基反应的影响为应用实例进行了研究,结果表明,Hg2 与CCl4的毒性有协同作用.     

贵州省万山汞矿区地表水中不同形态汞的空间分布特点

利用两次金汞齐-冷原子荧光光谱法,对贵州省废弃汞矿山万山矿区地表水不同形态汞(活性态、溶解态、颗粒态)的含量进行测定。样品活性态汞为1.04~402 ng／L;溶解态汞为12.5~426 ng／L;颗粒态汞变化很大,最低只有1.38 ng／L,最高达4 427 ng／L。研究表明:(1)直接与矿山冶炼活动排放物炉渣接触的溪流水污染程度最高,总汞高达4.46μg／L;(2)与矿山开采活动排放的废石或贫矿石接触的溪流水污染程度较低;(3)远离汞矿开采、冶炼活动区的地表水总汞接近汞矿化带背景参考值。     

扬子地块西南缘低温成矿域Au、Sb、Hg、As矿床区域分布上的共生分异及控制因素

扬子地块西南缘大面积低温成矿域的Au、Sb、Hg、As矿床,常出现共生分异的现象,在空间上形成Au、Sb、Hg、As矿床、矿带相伴出现而又相对独立的规律性分布。在详细研究Au、Sb、Hg、As矿床、矿带区域分布及其产出地质背景的基础上,从不同的角度,对制约Au、Sb、Hg、As矿床、矿带共生分异的因素进行了探讨。     

呼和浩特市不同粒径空气颗粒物中汞的分布规律

采用分级采样装置 ,于冬夏两季采集呼市三个不同功能区不同粒径空气颗粒物中的汞进行分析 ,结果表明 :呼市空气颗粒物中的汞含量冬季明显高于夏季 ;冬季空气颗粒物中的汞含量为居民区 >交通区 >对照区 ,夏季为交通区 >居民区 >对照区 ;空气中汞主要富集在可吸入粒子中。     

微型生物与金属腐蚀的研究

主要研究了海洋微生物与金属腐蚀的相关性。通过调查、分析海洋微生物的性质,尤其是硫酸盐还原菌（ＳＲＢ）,用移植埋片法对海底沉积物中ＳＲＢ含量的分析,建立了ＳＲＢ含量与腐蚀率之间的表象关系,为海洋工程设计提供了重要数据。